Do not. X-Rebirth was supposed to be it already.
Egosoft repeats itself -- just like history. You can imagine what that means.

Well, no Rebirth wasn't supposed to be it, unless my memory is failing me. I don't think they ever really tried to advertise Rebirth as "the next in the series of X games", and rather thought they tried to avoid giving the impression it was X4.

I don't mean to defend Rebirth (I've finally decided after all the years Egosoft spent improving it, I still just don't really like it as much as the earlier games), and there's no way I'm pre-ordering, both out of (learned) principle and (learned) experience with Egosoft, but still, let's keep a sense of perspective.

"I can say, in all conscience, that I believe that X4: Foundations is the space simulation with the most possibilities in space.

The biggest sandbox this side of the galaxy became, so to say, even bigger.

It is not neccessary to have played one of the precursers since the '99 release X: Beyond the frontier, or have read one of the many books from Helge T. Kautz, to be able to enjoy X4.
But we put in much effort to connect the game to this gigantic, established universe.
As such, even the new-comer gets the feeling to be around in an universe with a long pre-story.

One fundamental feature in the beginning, something that many missed with X: Rebirth: Yes, you can fly almost any ship in the universe, personally.

From small fighters, with you as a pilot and a two-man crew, up to giant carriers which can carry a whole fleet.

You can run around on the bridge and give the crew orders over the minimap and watch how they improve their abilities. But you can just as well go to the captain's console and take control of the ship yourself.
With this, the biggest challenge was to create a seamless change between those different sizes. This is especially visible when you decide for the first time to change from a station's platform to a ship.
You're running around on the station, climb into a small fighter's cockpit by a ladder, fly to a bigger frigatte, climb out and run to the cockpit of the frigatte, land this one on a carrier just to get off and go to the bridge, all without loadscreens or cutscenes, even when flying through jumpgates"